A Robust Frequency Domain Decision Feedback Equalization System for Uplink SC-FDMA Systems

In this paper, a robust iterative block decision feedback equalization (DFE) algorithm is developed for uplink single-carrier frequency division multiple access (SC-FDMA) systems. Three important problems that can adversely affect the performance of the DFE in SC-FDMA systems are to be addressed here, i.e., the feedback symbols reliability, the feedback correlation metric, and the phase noise due to inaccuracies in the fabrication process of the crystal oscillator. Instead of using all the detected symbols in the feedback loop of the DFE, only the highly reliable symbols are selected to be fed back. This results in the improvement of the error propagation, one of the common problems in a DFE. Also, the feedback correlation is an important metric in the design of the DFE, and hence an elegant method is proposed in this design and found to perform better than the available existing designs in the literature. Finally, the transmitter and receiver phase noise is iteratively compensated using its corresponding time- and frequency-domain properties. Simulation results demonstrate the robustness of our designed iterative block DFE.